Make loader lock new-allocated to avoid shutdown crash.

runtime/vm/service_isolate.cc

Index: runtime/vm/service_isolate.cc
diff --git a/runtime/vm/service_isolate.cc b/runtime/vm/service_isolate.cc
index e85a5c03de1d191e77df65061718d8a0c78a6ecb..19ccf685da512528ab8a910740a524d7ae549fb2 100644
--- a/runtime/vm/service_isolate.cc
+++ b/runtime/vm/service_isolate.cc
@@ -23,8 +23,6 @@
 
 namespace dart {
 
-DECLARE_FLAG(bool, shutdown);
-
 #define Z (T->zone())
 
 
@@ -462,9 +460,6 @@ void ServiceIsolate::Run() {
 
 
 void ServiceIsolate::KillServiceIsolate() {
-  if (!FLAG_shutdown) {
-    return;
-  }
   {
     MonitorLocker ml(monitor_);
     shutting_down_ = true;